The present invention relates to an implantable cardiac prosthesis and, more particularly, to a prosthesis that may be implanted at an annulus of a heart valve to help improve operation of a defective or damaged valve.
A heart valve may become defective or damaged, such as resulting from congenital malformation, disease, or aging. When the valve becomes defective or damaged, the leaflets may not function properly. One common problem associated with a degenerating heart valve is an enlargement of the valve annulus (e.g., dilation). Other problems that may result in valve dysfunction are chordal elongation and lesions developing on one or more of the leaflets.
The bicuspid or mitral valve is located in the left atrioventricular opening of the heart for passing blood unidirectionally from the left atrium to the left ventricle of the heart. The mitral valve is encircled by a dense fibrous annular ring and includes two valve leaflets of unequal size. A larger valve leaflet, which is known as the anterior leaflet, is located adjacent the aortic opening. The smaller leaflet is the posterior leaflet.
When a mitral valve functions properly, for example, it prevents regurgitation of blood from the ventricle into the atrium when the ventricle contracts. In order to withstand the substantial backpressure and prevent regurgitation of blood into the atrium during the ventricular contraction, the cusps are held in place by fibrous cords (cordae tendinae) that anchor the valve cusps to the muscular wall of the heart.
By way of example, if an annulus enlarges or dilates to a point where the attached leaflets are unable to fully close (malcoaptation), regurgitation or valve prolapse may occur. Adverse clinical symptoms, such as chest pain, cardiac arrhythmias, dyspnea, may manifest in response to valve prolapse or regurgitation. As a result, surgical correction, either by valve repair procedures or by valve replacement, may be required.
Surgical reconstruction or repair procedures may include plication, chordal shortening, or chordal replacement. Another common repair procedure relates to remodelling of the valve annulus (e.g., annuloplasty), which may be accomplished by implantation of a prosthetic ring to help stabilize the annulus and to correct or help prevent valvular insufficiency which may result from defect or dysfunction of the valve annulus. Properly sizing and implanting the annuloplasty ring can substantially restore the valve annulus restored to its normal, undilated, circumference. In situations where the valve leaflets exhibit lesions, it also may be necessary to reconstruct one or more valve leaflets by securing grafts or patches to the leaflets, such as over lesions or holes formed in the leaflet. The repair or reconstruction of the leaflets may be complicated and time consuming, the results of which are not readily reproducible.
The present invention relates to a cardiac prosthesis that may be implanted at an annulus of a heart valve to help improve operation of a defective or damaged valve. The apparatus includes a base portion, which may be attached to the valve annulus for providing support at the annulus. A buttress portion extends from the base portion, such as in a radially inwardly and generally axially manner. When the apparatus is implanted at an annulus of a heart valve, the buttress provides a surface against which one or more leaflets (depending on the type of heart valve) may move into and out of engagement. When the leaflet engages or coapts with the buttress, flow of blood through the apparatus and valve is inhibited, thereby mitigating regurgitation. The apparatus also permits the flow of blood through the apparatus and valve as the leaflet is urged away from the buttress.
An aspect of the present invention provides an apparatus for helping improve operation of a heart valve. The apparatus includes a generally annular base. A buttress extends generally axially from and inwardly relative to an arc portion of the base for, when implanted, providing a surface with which a leaflet of the heart valve may move into and out of engagement for controlling blood flow relative to the apparatus.
Another aspect of the present invention provides an apparatus for helping improve operation of a heart valve. The apparatus includes a frame having a generally annular base portion and a support portion extending generally axially and inwardly relative to the base portion. The support portion terminates at a distal end spaced from the base portion. A sheath of a flexible material covers the frame to form a buttress extending between the base portion and the distal end of the support portion. As a result, when the apparatus is implanted, the buttress provides a surface with which a leaflet of the heart valve may move into and out of engagement.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.